Re: printf without spaces

Thanks, Karim.

On 15 August 2018 at 16:36, Karim Belabas <Karim.Belabas@math.u-bordeaux.fr> wrote:

* John Cremona [2018-08-15 16:51]:
> I would like formatted printing of a list (of positive integers) with no
> embedded spaces. The %s conversion inserts spaces:
>
> ? v = vector(10,j,j)
> %80 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
> ? printf("%s", v)
> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>
> (there's a space after each comma). Is that possible with some more %
> magic? I could not see how to.

Not really. You can

1) (globally) set 'output' to 0 [ changing globals is not a good
programming practice ]

2) print each element individually [ cumbersome but can be done once and for all]

vtostr(v) =
{ my (w, n = #v);
if (!n, return (""));
w = vector(n);
for (i = 1, n-1, w[i] = Str(v[i],","));
w[n] = Str(v[n]);
concat(w);
}
? printf("[%s]", vtostr(v))
[1,2,3,4,5,6,7,8,9,10]

Maybe someone else will have a better idea :-)

I'll use that. By the way in my original message I mentioned fprintf since I had seen it in the manual but in fact it is given as an example:

fprintf(file,format,args[..]) = write(file,call(Strprintf,[format,args]));

So I put that into my script and it works like a charm.

> Second question: in the first line above is there an easier way to get a
> range of consecutive integers into a list?

v = [1..10];

You'll have to believe me that I looked for this....

Thanks again,

John

Cheers,

K.B.
--
Karim Belabas, IMB (UMR 5251) Tel: (+33) (0)5 40 00 26 17
Universite de Bordeaux Fax: (+33) (0)5 40 00 21 23
351, cours de la Liberation http://www.math.u-bordeaux.fr/~kbelabas/
F-33405 Talence (France) http://pari.math.u-bordeaux.fr/ [PARI/GP]
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